Filbey Francesca Mapua, Russell Tamara, Morris Robin G, Murray Robin M, McDonald Colm
The Mind Research Network, Albuquerque, New Mexico, USA.
Ann Gen Psychiatry. 2008 Oct 3;7:18. doi: 10.1186/1744-859X-7-18.
Presumed obligate carriers (POCs) are the first-degree relatives of people with schizophrenia who, although do not exhibit the disorder, are in direct lineage of it. Thus, this subpopulation of first-degree relatives could provide very important information with regard to the investigation of endophenotypes for schizophrenia that could clarify the often contradictory findings in schizophrenia high-risk populations. To date, despite the extant literature on schizophrenia endophenotypes, we are only aware of one other study that examined the neural mechanisms that underlie cognitive abnormalities in this group. The aim of this study was to investigate whether a more homogeneous group of relatives, such as POCs, have neural abnormalities that may be related to schizophrenia.
We used functional magnetic resonance imaging (fMRI) to collect blood oxygenated level dependent (BOLD) response data in six POCs and eight unrelated healthy controls while performing under conditions of sustained, selective and divided attention.
The POCs indicated alterations in a widely distributed network of regions involved in attention processes, such as the prefrontal and temporal (including the parahippocampal gyrus) cortices, in addition to the anterior cingulate gyrus. More specifically, a general reduction in BOLD response was found in these areas compared to the healthy participants during attention processes.
These preliminary findings of decreased activity in POCs indicate that this more homogeneous population of unaffected relatives share similar neural abnormalities with people with schizophrenia, suggesting that reduced BOLD activity in the attention network may be an intermediate marker for schizophrenia.
推定的 obligate 携带者（POCs）是精神分裂症患者的一级亲属，他们虽然未表现出该疾病，但处于其直系血统中。因此，这一一级亲属亚群可为精神分裂症内表型的研究提供非常重要的信息，有助于阐明精神分裂症高危人群中常常相互矛盾的研究结果。迄今为止，尽管已有关于精神分裂症内表型的文献，但我们仅知晓另一项研究探讨了该群体认知异常背后的神经机制。本研究的目的是调查一个更同质的亲属群体，如 POCs，是否存在可能与精神分裂症相关的神经异常。
我们使用功能磁共振成像（fMRI）在 6 名 POCs 和 8 名无血缘关系的健康对照者执行持续、选择性和分散注意力任务时，收集血氧水平依赖（BOLD）反应数据。
POCs 显示出在广泛分布的参与注意力过程的区域网络中存在改变，如前额叶和颞叶（包括海马旁回）皮质，以及前扣带回。更具体地说，与健康参与者相比，在注意力过程中这些区域的 BOLD 反应普遍降低。
POCs 活动降低的这些初步发现表明，这一未受影响的更同质亲属群体与精神分裂症患者存在相似的神经异常，提示注意力网络中 BOLD 活动降低可能是精神分裂症的一个中间标志物。
